A 60 year old male is admitted with a 2days history of lower abdominal pain and marked vomiting. On examination he has abdominal swelling, guarding and numerous audible bowel sounds. What is the likely diagnosis?

The key is D: sigmoid volvulus [History is not suggestive of ischemic colitis. There are no bowel sounds heard in gallstone ileus. Small bowel obstruction causes central abdominal pain, So given features with lower abdominal pain makes it more likely to be sigmoid volvulus].